Sawchains of chainsaws mounted on, for example, harvester equipment for the felling and processing of tree trunks often run with high peripheral speeds (>50 m/s) around the guide bar. Although chain breakages occur relatively seldom, they can cause serious personal injury if one or more links are freed and are thrown as a projectile from a broken part of the chain, in the manner shown highly approximately and schematically illustrated in the sequence 1-6 in FIGS. 5 and 6 of the attached drawings. This type of chain breakage or chain shot can be considered to be particularly dangerous, since the operator of the equipment often sits in the possible direction that such a chain shot may take. Authorities have for this reason issued regulations concerning protection from chain shot for the type of chainsaw described.
In one form of protection from chain shot shown in EP 1 528 852 C, a protective wall is arranged that carries out a pivot motion together with the guide bar at the rear section of the latter, approximately in the manner that is shown by dot-dash lines in the attached FIG. 5. It may not always be possible, however, for such a protection from chain shot to prevent chain shot when it is used together with a chainsaw that, furthermore, has an external rear shield that forms a part of a saw box. There may in this case still be a risk that the broken part of the chain comes to a location outside of the shield and is ripped off by the edge of some opening, particularly when the guide bar is located at its swivelled out location.